1. Field of the Invention
The present invention relates to a recording apparatus and, more particularly, to the movement of the recording section thereof.
2. Description of the Prior Art
In recording apparatuses such as, for example, thermal printers, wire-dot printers, and further, word-processors, a typewriters, etc., more functions and higher performance are being realized. Particularly, in a typewriter and the like which can edit and the like, the burden for the operator is reduced and persons other than the operators, who were specially and well trained, can make a high grade document.
However, among such many functions, there are also functions which are particularly useful for only the operators who are relatively experienced and which are not well suited for use by a beginner. Therefore, it is difficult for the beginner to use such an apparatus.
For example, the ribbon lifting operation when recording is also one of such inconvenient functions.
A typewriter as a conventional recording apparatus of this kind, in particular, will now be described with reference to FIGS. 1 to 3.
FIG. 1 is an illustration for explaining the external appearance of the typewriter. A keyboard 1 is disposed on the upper surface on this side of the typewriter. The recording is performed on a recording paper 4, wrapped around a platen 3, by a type wheel 6 attached to a carriage 2 which is reciprocated horizontally.
The type wheel 6 is disposed on the side of the platen 3 of the carriage 2 and is rotated by a motor (not shown).
FIG. 2 is a perspective view of the recording section and FIG. 3 is a side elevational view. A hammer unit 7 is disposed on this side of the type wheel 6. A hammer 7a is attached to the point of the hammer unit 7.
Also, a print ribbon cassette 8 is detachably attached over the carriage 2.
The print ribbon cassette 8 has left and right arms 8a and 8b. The print ribbon pulled out from the side of the arm 8b is led in the side of the other arm 8a and is wound in the print ribbon cassette 8. This print ribbon passes through the gap between the type wheel 6 and the platen 3 as indicated at a numeral 8c in FIG. 3.
On the other hand, the print ribbon cassette 8 is rotatably supported to the side of the carriage 2 through stub shafts 8d. When the cassette 8 is installed over the carriage 2, it is retained by hooks 5 so as not to be detached.
In addition, a torsion coil spring 10 is disposed below the print ribbon cassette 8. One end of the spring 10 is stopped on the carriage side, while the other is in contact with the bottom surface of the print ribbon cassette 8.
A solenoid 9 is disposed below the bottom surface on the side of the print ribbon cassette 8 near the print wheel 6. A rod 9a of the solenoid 9 is in contact with the bottom surface of the print ribbon cassette 8. When no current is supplied to the solenoid 9, the rod 9a is located in the lower position. In this state, the print ribbon cassette 8 is rotated clockwise in FIG. 3 by the torsion coil spring 10, so that the print ribbon 8c is in the state dropped from the printing position.
Upon printing, when a signal is inputted from the keyboard, the solenoid 9 is excited and the rod 9a is projected upwardly, so that the print ribbon cassette 8 is rotated counterclockwise in FIG. 3 and the print ribbon 8c reaches the printing position.
In this way, whenever the printing is performed by operating the keyboard, the print ribbon is lifted to the printing position and is immediately shifted from the printing position after the printing, thereby enabling the print to be checked.
However, this ribbon lifting operation has drawbacks such that the solenoid 9 has to be driven and extremely large noise is generated since the rod 9a is brought into contact with the print ribbon cassette 8.
Therefore, recently, in the case where the printing is continuously performed, the ribbon lifting operation is not performed for every character but printing is executed while the lifted state is held under electronic control.
Namely, when a signal from the next print key is inputted within a certain preset time interval after printing a prior character, the lifted state is maintained to eliminate the noise in association with the ribbon lifting operation and to eliminate the time necessary for the lifting, thereby realizing essentially silent and high-speed operation. FIG. 4 shows the flowchart in this case. In step 1, when a key signal is inputted, the ribbon shifting operation is performed in step 2. The type corresponding to the key input is selected from the type wheel 6 or the like in step 3. The printing hammer 7a is driven in step 4 and the next key signal is checked to see if it is inputted or not in step 5. If the next key signal is inputted, the processing is returned to step S2. If the next key signal is not inputted in step 6, the discrimination is made to see if the waiting time t.sub.n (e.g., 200 msec) has elapsed or not. If the waiting time t.sub.n has not elapsed yet, the processing will be returned to step 5. If it has elapsed, the ribbon dropping operation will be executed in step 7.
However, in the case where the characters which have been once stored in a memory by the key inputs are recorded and printed at once in the W/W mode (the recording is performed on a word unit basis), L/L mode (the recording is performed on a line unit basis), etc., the ribbon lifting operation is controlled and the printing can be performed while the ribbon is in the lifted state without carrying out the ribbon lifting and dropping operations whenever one character is printed. However, in the typewriters having only the ordinary C/C mode ( the recording is performed on a character unit basis) without such modes, the waiting time t.sub.n of FIG. 4 is determined on the basis of the experienced operator as a reference. If these typewriters are operated by a beginner whose printing operation speed is slow, the ribbon will have been lifted and dropped whenever the printing is performed, so that the noise is generated and the time necessary for lifting the ribbon is also added to the printing speed as a whole. Therefore, the typing speed will be slow.